Determination of phenobarbitone and carbamazepine concentration in plasma by RP-HPLC

OBJECTIVE:To establish a method for rapid determination of phenobarbition and carbamazepine in human plasma.METHODS:Using RP HPLC with estazolam as internal standard to determine concentration of phenobarbitone and carbamazepine in human plasma. The separation was performed on shimadzu shimpack CLC C 18 column with methanol water (60∶40) as mobile phase . The flow rate was 0.8 ml·min -1 . The wavelength for detection was 254 nm.RESULTS:The linear ranges of phenobarbitone was between 3～60 μg·ml -1 with r = 0.999 8 , carbamazepine was between 2～16 μg·ml -1 with r = 0.999 5 . The lowest limit of detection was 11.57 ng·ml -1 and 4.92 ng·ml -1 . The average recoveries for phenobarbitone and carbamazepine in three different concentrations were 99.92 %, 101.30 %, 97.92 % and 99.41 %, 101.52 %, 98.22 %( n =9). The RSDs of intraday were 3.1 %, 2.6 %, 3.8 % and 1.9 %, 1.6 %, 6.3 % ( n =5). The RSDs of interday were 2.9 %, 2.5 %, 4.8 % and 1.8 %, 2.3 %, 2.9 % ( n =9). CONCLUSIONS:This method is accurate, rapid, with high sensitivity and good repeatability. It can be used as a roution method by TDM. [